Liquid scintillation counting is a type of analysis test which has been used for many biological research applications and is a highly efficient system for detection of low energy radiation such as .sup.14 C and .sup.3 H. One of its primary advantages over other radiation detections systems is that the sample is placed within the detector, whereas in other systems the radioactive sample is brought only near the sample and must pass through a barrier (e.g. air or gaseous medium) which stop .sup.3 H or .sup.14 C emissions from reaching the detector. With liquid scintillation counting, the radiation has a better chance of being detected since it is within the detector.
In liquid scintillation counting, many biochemical experiments dictate the use of membrane filters to trap radioactive material. These filters, along with the radioactive sample, are placed in a liquid scintillation counter for radioactive detection. In the past, the use of such filters within the liquid scintillation counter has introduced problems which adversely effect the efficiency of radiation counting. First, some potential radiation counts are absorbed by the filter and not counted by the detector. Second, the radioactive material in solution is counted at a different efficiency rate than the mass of material still attached to or on the filters. It is an object of the present invention to find an answer to such problems whereby maximum efficiency of counting is realized for the radioactive samples contained on filters in liquid scintillation counters.